Bud variation

“ It deserves notice that all the plants which have yielded bud-variations have likewise varied greatly by seed.
These plants belong to so many orders that we may infer that almost every plant would be liable to bud-variation if placed under the proper exciting conditions. These conditions, as far as we can judge, mainly depend on long-continued and high cultivation; for almost all the plants in the foregoing lists are perennials, and have been largely propagated in many soils and under different climates, by cuttings, offsets, bulbs, tubers, and especially by budding or grafting. ”

“ A marked bud-variation is of very rare occurrence, but in many cases the tendency of plants raised from seeds to differ from the parents is so great that choice varieties are propagated entirely by buds. ”

“ Buds of all kinds, whether produced on ordinary branches or on subterranean stems, whether simple or much modified and supplied with a stock of nutriment, as in tubers and bulbs, are all liable to sudden variations of the same general nature.
In the list, many of the cases are certainly due to reversion to characters not acquired from a cross, but which were formerly present and have since been lost for a longer or shorter time;—as when a bud on a variegated plant produces plain leaves, or when the variously-coloured flowers of the Chrysanthemum revert to the aboriginal yellow tint. ”

“ Variegated plants, whether originally produced from seeds or buds, can generally be propagated by budding, grafting, etc.; but all are apt to revert by bud-variation to their ordinary foliage. This tendency, however, differs much in the varieties of even the same species; for instance, the golden-striped variety of Euonymus japonicus “is very liable to run back to the green-leaved, while the silver-striped variety hardly ever changes.” ”

“ Spores, which are of the nature of buds, taken from such abnormal fronds, reproduce, with remarkable fidelity, the same variety, after passing through the sexual stage. [61] With respect to colour, leaves often become by bud-variation zoned, blotched, or spotted with white, yellow, and red; and this occasionally occurs even with plants in a state of nature. Variegation, however, appears still more frequently in plants produced from seed; even the cotyledons or seed-leaves being thus affected. [62] There have been endless disputes whether variegation should be considered as a disease. ”

“ Although I have been able to collect a good many cases of bud-variation, as shown in the previous lists, and might probably, by searching foreign horticultural works, have collected more cases, yet their total number is as nothing in comparison with that of seminal varieties. With seedlings raised from the more variable cultivated plants, the variations are almost infinitely numerous, but their differences are generally slight: only at long intervals of time a strongly marked modification appears. ”

“ Hardly a single plant can be named, which has long been cultivated and propagated by seed, that is not highly variable; common rye (Secale cereale) has afforded fewer and less marked varieties than almost any other cultivated plant; [4] but it may be doubted whether the variations of this, the least valuable of all our cereals, have been closely observed.
Bud-variation, which was fully discussed in a former chapter, shows us that variability may be quite independent of seminal reproduction, and likewise of reversion to long-lost ancestral characters. ”

“ We should also bear in mind that distinct varieties, and even distinct species,—as in the case of peaches, nectarines, and apricots,—of certain roses and camellias,—although separated by a vast number of generations from any progenitor in common, and although cultivated under diversified conditions, have yielded by bud-variation closely analogous varieties. ”

“ On the other hand there is a larger group of cases of reversion by buds, which is probably not of hybrid nature, nor due to innate inconstancy of the variety, but must be considered as pure atavism. I refer to the bud-variations of so many of our cultivated varieties of shrubs and trees. Many of them are cultivated because of their foliage. They are propagated by grafting, and in most cases it is probable that all the numerous specimens [179] of the same variety have been derived in this way from one primitive, aberrant individual. ”

“ As a single bud out of many thousands produced year after year on the same tree under uniform conditions, has been known suddenly to assume a new character; and as buds on distinct trees, growing under different conditions, have sometimes yielded nearly the same variety—for instance, buds on peach-trees producing nectarines, and buds on common roses producing moss-roses—we clearly see that the nature of the conditions is of subordinate importance in comparison with the nature of the organism in determining each particular form of variation ”

“ When we reflect on the millions of buds which many trees have produced, before some one bud has varied, we are lost in wonder as to what the precise cause of each variation can be. Let us recall the case given by Andrew Knight of the forty-year-old tree of the yellow magnum bonum plum, an old variety which has been propagated by grafts on various stocks for a very long period throughout Europe and North America, and on which a single bud suddenly produced the red magnum bonum. ”

“ When the tendency to reversion affects many buds on the same tree, it becomes covered with different kinds of leaves, flowers, or fruit; but there is reason to believe that such fluctuating varieties have generally arisen from seed. It is well known that, out of a number of seedling varieties, some transmit their character much more truly by seed than others; so with bud-varieties some retain their character by successive buds more truly than others ”

“ This resemblance, or rather identity, is rendered far more striking if the facts can be trusted which apparently render it probable that the cellular tissue of one species or variety, when budded or grafted on another, may give rise to a bud having an intermediate character. In this chapter we clearly see that variability is not necessarily contingent on sexual generation, though much more frequently its concomitant than on bud-reproduction. ”

“ But if we turn to the other end of the series, namely, to such cases as that of a peach-tree which, after having been cultivated by tens of thousands during many years in many countries, and after having annually produced thousands of buds, all of which have apparently been exposed to precisely the same conditions, yet at last suddenly produces a single bud with its whole character greatly transformed, we are driven to an opposite conclusion. ”

“ The pupils should notice that the buds are always just above the large triangular scars. If they are still in doubt as to the cause of these marks, show them some house-plant with well-developed buds in the axils of the leaves, and ask them to compare the position of these buds with their branches. The buds that spring from the inner angle of the leaf with the stem are axillary buds; those that crown the stems are terminal. Since a bud is an undeveloped branch, terminal buds carry, on the axis which they crown, axillary buds give rise to side-shoots. ”

“ The buds that appear on roots are unusual or abnormal,—they occur only occasionally and in no definite order. Buds appearing in unusual places on any part of the plant are called adventitious buds. Such usually are the buds that arise when a large limb is cut off, and from which suckers or water-sprouts arise.
Fig. 144.—Opening Pear Leaf-bud.
How Buds Open.—When the bud swells, the scales are pushed apart, the little axis elongates and pushes out. In most plants the outside scales fall very soon, leaving a little ring of scars. ”

“ Those, however, who have not got a theory to save by [546] putting anomalies out of sight, may be inclined to think that the occurrence of buds where they are avowedly unconnected with nodes, and are axillary to nothing, tells very much against the assumption that every bud implies a node and a corresponding foliar organ. And they may also see that the development of these adventitious buds at places where there is excess of nutritive materials, favours the view above set forth. ”

“ By buds indeed, as we well know, plants are propagated, and in that sense each bud is a separate being, or a young plant in itself; but such propagation is only the extension of an individual, and not a reproduction of the species as by seed. Accordingly, all plants increased by buds, cuttings, layers or roots, retain precisely the peculiar qualities of the individual to which they owe their origin. If those qualities differ from what are common to the species, sufficiently to constitute what is called a variety, that variety is perpetuated through all the progeny thus obtained. ”

“ From what we have seen since of bud structure, we may now make our type more complete by giving each bud a root proportioned to its size. And our elementary type of tree plant will be as in Fig. 46.
§ 7. Now these three buds, though differently placed, have all one mind. No bud has an oblique mind. Every one would like, if he could, to grow upright, and it is because the midmost one has entirely his own way in this matter, that he is largest. He is an elder brother;—his birthright is to grow straight towards the sky. ”

“ A more common practice, called budding, or inoculating, is to insert a bud of one tree, accompanied by a portion of its bark, into the bark of another, and the tree which is thus engrafted upon is called the stock. By this mode different kinds of fruits, as apples, pears, plums, &c., each of which is only a variety accidentally raised from seed, but no further perpetuated in the same manner, are multiplied, buds of the kind wanted to be propagated being engrafted on so many stocks of a wild nature. ”

“ A new leaf is sent up every year from the tip end of the root-stock, and the old, dropping off, leaves a sear, which is the "seal." Buds formed on these underground stems are protected from too great changes of temperature by a few inches of soil. Those buds that lie on the surface must be protected by the dead leaves which fall in autumn. They, the buds, are the real "babes in the wood," you see.
Our baby bud, just like children, must have nourishment as well as protection in order to grow in spring. This is provided by the thick leaves that cover, or by the stem, or in some other way. ”

“ By this means the bud is, as it were, planted in the bark of the tree.
The worsted must not be bound exactly over the bud, or it might bruise or break it. The bud should have the appearance of peeping out between the turns of worsted. When the operation is finished it can be left a week or two, and by that time you will know whether it has taken or not by the appearance of the bud. As soon as you are sure that it has taken, the ties or worsted can be loosened, not taken off; they may want relaxing several times as the little bud swells and grows. ”

“ Dormant buds, or preventitious buds, are such as receive no sufficient supply of water and food materials to enable them to open with the other buds in ordinary years, for in most trees only the upper buds on the branches develop into new shoots. The lower buds do not die, however, but merely keep pace with the growth in thickness of the parent branch, and may be elongated sufficiently each year to raise the minute tips level with the bark, their proper cambium only remaining alive but not thickening the bud. ”

“ The body c has lost its leaves through some accident, and its growth has ceased. In other words, the parts at aaaa are like the shoot fh, except that they are shorter, and they are of the same age. One grew from the end or terminal bud of the main branch, and the others from the side or lateral buds. Parts or bodies that bear leaves are, therefore, branches.—The buds at bbbb have no leaves, and they remain the same [119] size that they were a year ago. They are dormant. The only way for a mature bud to grow is by making leaves for itself, for a leaf will never stand below it again. ”

“ Definite annual Growth from winter buds is marked in most of the shoots from strong buds, such as those of the Horse-chestnut and Hickory (Fig. 72, 73) . Such a bud generally contains, already formed in miniature, all or a great part of the leaves and joints of stem it is to produce, makes its whole growth in length in the course of a few weeks, or sometimes even in a few days, and then forms and ripens its buds for the next year's similar growth. ”

“ A week spent in the rich soil and hot, humid atmosphere of the forcing-house causes the bud to swell and begin to grow. In ten days it is seen to have really made some appreciable growth. At the end of fourteen days the creamy-white, tightly-folded foliage leaves and the tip of the flower-stem are seen to have developed, the leaves broadening out somewhat about the eighteenth day. In twenty-one days the still folded leaves have gained a delicate, pale greenish hue, and the flower-buds have begun to make themselves plainly visible upon the flower-stem. ”

“ From amid the crown of leaves shoots forth a bud upon a stalk, and resembling a large green flower-bud. This shoots up rapidly, and becomes as rapidly too heavy for its stalk, which bends under its weight. The bud now bends down to the stem and grows as large probably as a cocoa-nut, its form being like that of a Provence rose-bud, and of a dark violet colour. I saw upon almost all banana-trees, even on those which bore rich clusters of ripe fruit, this immense violet-coloured bud hanging, and was not a little curious to know all about it. ”